Apparatus for processing tissue for electron microscope examination

ABSTRACT

Apparatus for processing tissue for electron microscope examination comprises a series of processing reagent containing receptacles arranged in an annular row, a rotary transfer disc for transferring a tissue-containing basket along the series of receptacles successively one by one to dip the basket and the tissue contained therein into each of the reagents in the receptacles, and means for maintaining the atmosphere surrounding some of the reagents at sub-atmospheric pressure when the basket and the tissue therein are being dipped therein for processing, the sub-atmospheric pressure improving and accelerating ingress and impregnation of the reagents into the tissue being processed.

United States Patent 1191 Takahashi May 7, 1974 1 APPARATUS FOR PROCESSING TISSUE 3,338,207 8/1967 Kling 118/429 x FOR ELECTRON MICROSCOPE 3,412,667 11/1968 Hunt 118/425 X EXAMINATION Kikuo Takahashi, Narashino, Japan Sakura Seiki Kabushiki, Kaisha, Tokyo, Japan Filed: Nov. 10, 1972 Appl. No.: 305,583

Inventor:

Assignee:

References Cited UNITED STATES PATENTS 7/1953 Fisher 118/425 UX 3/1955 Schell 118/64 X 2/1944 Weiskopf... 118/425 X 7/1958 Cohen 118/57 X Primary Examiner-Morris Kaplan Attorney, Agent, or FirmWaters, Roditi, Schwartz & Nissen [5 7] ABSTRACT Apparatus for processing tissue for electron microscope examination comprises a series of processing reagent containing receptacles arranged in an annular row, a rotary transfer disc for transferring a tissuecontaining basket along the series of receptacles successively one by one to dip the basket and the tissue contained therein into each of the reagents in the receptacles, and means for maintaining the atmosphere surrounding some of the reagents at sub-atmospheric pressure when the basket and the tissue therein are being dipped therein for processing, the subatmospheric pressure improving and accelerating ingress and impregnation of the reagents into the tissue being processed.

10 Claims, 9 Drawing Figures PATENTEDIM 1 mu SHEU 1 [IF 5 FIG. 3

Pmmenm 1 1914 3305.008.

SHEET 2 OF 5 FIG. 2

PA'TENTEDm 1 m4 SHEET Q [If 5 FIG. 7

mmmw 719m 3.809.008

SHEET 5 OF 5 vAHK APPARATUS FOR PROCESSING TISSUE FOR ELECTRON MICROSCOPE EXAMINATION BACKGROUND OF THE INVENTION This invention relates to apparatus for processing tissue for electron microscope examination and, more particularly, to an apparatus for preparing histologic tissue for subsequent examination by an electron microscope.

It is well known that, for carrying out histologic examination of part of a living body, a tissue specimen of the living body is cut from the body and sliced into a number of thin pieces, which are fixed, dehydrated and otherwise processed or treated in a tissue processing apparatus. After having been processed by the processing apparatus, the thin pieces or specimens are again sliced into extremely thin pieces, which are used for subsequent electron microscope examination.

Heretofore known tissue processing apparatus generally comprises a series of receptacles respectively containing different liquid reagents therein and arranged in an annular endless row, and a rotary indexing transfer disc disposed above the receptacles in concentric relation to the annular row and having on the peripheral portion thereof at least one basket suspended therefrom and adapted to receive therein tissue to be processed, the basket and, therefore, the tissue therein being dipped into the different liquid reagents contained in the successively arranged receptacles one by one when the transfer disc is rotated or indexed and moved up and down.

In treating or processing tissue with such a processing apparatus, difficulties have been encountered in rapidly and throughly impregnating the reagents into the tissue being processed because a fresh tissue generally has a characteristic of resisting rapid and uniform ingress of the reagents thereinto because it contains considerable quantities of air bubbles and moisture. It is also difficult to attain rapid and thorough impregnation of the reagent into the tissue especially when the reagent is a highly viscous liquid.

SUMMARY OF THE INVENTION It is, therefore, an object of this invention to provide a new and improved apparatus for processing tissue for electron microscope examination which enables rapid impregnation of reagents into tissue being processed, thus realizing thorough and uniform processing of the tissue.

' Another object of this invention is to provide an apparatus of the above stated nature wherein the local atmosphere surrounding at least one reagent is maintained at sub-atmospheric pressure while a tissue is being dipped in the reagent whereby air bubbles existing in the tissue are rapidly removed to leave void spaces which enables the reagent to rapidly enter the tissue for the processing thereof.

A further object of this invention is to provide an apparatus of the above stated nature wherein a basket containing tissue therein is held stationary for a while after it has been raised from a viscous processing reagent contained in a receptacle, whereby the viscous reagent remaining in the basket is allowed to drip into the receptacle, whereby carryover of the viscous reagent by the basket into the next reagent receptacle is prevented.

Still another object of this invention is to provide an apparatus of the above stated nature wherein reagent receptacles other than a receptacle in which a tissue basket is being dipped in reagent are covered by lids whereby evaporation of reagents in such receptacles is prevented.

A still further object of this invention is to provide an apparatus of the above stated nature wherein processing of tissue by reagents is carried out in a sealed hood from within which air is continually exhausted and which prevents dust infiltration.

It is also an object of this invention to provide an apparatus of the above stated nature wherein processing of tissue by reagents is carried out in a sealed hood into which dry air is always supplied.

According to this invention, briefly summarized, there is provided an apparatus for processing tissue for electron microscope examination comprising means for arranging a series of processing reagent containing receptacles in a row with equal distances therebetween, and transfer means for transferring a tissue-containing basket, the transfer means being located above the re"- ceptacles and mounted for indexing movement along the series of receptacles and for up and down movement to dip the basket and tissue therein into the processing agents successively one by one, said apparatus incorporating the improvement comprising sealing means associated with the transfer means and operative to seal temporarily from the outside the ambient atmosphere surrounding any receptacle in which the basket is being dipped in the reagent, and suction means associated with at least some of the receptacles to evacuate air from the atmosphere surrounding said some receptacles thus sealed.

The nature, principle, and utility of this invention will be apparent from the following detailed description of the invention with respect to a preferred embodiment thereof when read in conjunction with the accompanying drawings, in which like parts are designated by like reference numerals.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a perspective view showing principally the front exterior of an example of the processing apparatus according to this invention;

FIG. 2 is a front elevation, in vertical section, of the apparatus shown in FIG. 1;

FIG. 2A is a plan view taken along the line "A IIA of FIG. 2;

FIG. 2B is a plan view taken along the line IIB IIB of FIG. 2;

FIG. 3 is a fragmentary perspective view showing a rotary transfer disc, a series of reagent receptacles, and other members associated therewith;

FIG. 4 is a diagrammatic plan view showing the receptacles disposed in an annular row;

FIG. 5 is a fragmentary front elevation, in vertical section, on an enlarged scale, showing one of the reagent receptacles, sealing cap, suction pipe and related FIG. 6 is a front elevation showing a dry air supply sytem and a basket oscillation system; and

FIG. 7 is a wiring diagram showing an electric circuit for controlling an indexing delay device.

DETAILED DESCRIPTION OF THE INVENTION General Principle Referring to FIG. 1, the apparatus for processing tissue for electron microscope examination according to this invention is generally designated by reference numeral 2 and comprises a lower housing 3 with front doors 3a, and a transparent upper cylindrical hood 4 mounted on the housing.

As shown in FIG. 2, there is provided a rotary transfer disc 5 within the hood 4. The disc 5 is rigidly supported on the top of a central rotary shaft 6 which is capable of vertical reciprocating motion and of intermittent rotary motion as is described hereinafter in detail. As is also shown in FIG. 3, the rotary disc 5 has on the lower surface thereof a series of vertical mounting rods 7 extending downward from the surface and arranged along the periphery of the disc 5 in angularly equally spaced-apart relationship. In one example, the number of such rods 7 is twenty. One of these rods 7 has on the lower end thereof a sealing cap 8 which will be described hereinafter in more detail. A basket 9 depends from within the cap 8, which basket is adapted to receive therewithin a tissue or specimen to be processed by the apparatus. Each of the remaining rods 7 has on the lower end thereof a lid 10 suspended from the rod by means of a flexible string 11.

Below the rotary disc 5, there are provided a series of beakers or receptacles 12 disposed in an annular row in vertically opposed relationship to the respective rods 7. The receptacles 12 are supported by a stationary structure 13 (FIG. 3) and are adapted to receive different kinds of processing liquids or reagents.

In the example shown, the number of the receptacles 12 is twenty which corresponds to the number of the rods 7. In the diagrammatical view of FIG. 4 showing the arrangement of the receptacles, the twenty receptacles are successively numbered 1 to 20.

At the beginning of operation of the apparatus, the rotary disc 5 is in a raised position as shown in FIGS. 2 and 3, so that the basket 9 and lids 10 are also in a raised position spaced apart upward from the receptacles 12. In this position, the rotary disc 5 is manually adjusted so that the rod 7 carrying the basket 9 is in vertical alignment with the receptacle 12 which is numbered 1 in FIG. 4.

When the apparatus is put in operation, the disc 5 is lowered by the downward movement of the shaft 6 until the basket 9 containing a specimen therein is completely immersed in the reargent contained in the receptacle numbered 1". After a predetermined time interval, the shaft 6 and, therefore, the disc 5 are raised to the original position, and then the rotary transfer disc 5 is indexed to a position where the basket 9 is in vertical alignment with the adjoining or next receptacle indentified as 2 in FIG. 4. Then, the indexed-disc 5 is again lowered by the downward displacement of the shaft 6 until the basket 9 is immersed in the liquid reagent contained in the receptacle numbered 2 for a predetermined time interval. The disc and, therefore, the basket 9 are again raised to the former position, and then similar indexing and up and down movement of the basket 9 is repeated until the basket has been immersed in the liquid reagent contained in the last receptacle numbered 20 in FIG. 4. During this operation, the liquid reagents in the receptacles are kept at predetermined different temperatures in a predetermined sequence. Thus, it will be seen that the tissue or specimen contained in the basket 9 successively undergoes chemical processing by the different kinds of liquid reagents.

A typical example of such a chemical processing is given in the following table.

Receptacle Time Temp. No. Reagents Interval in "C in minute I 2.5% Glutaraldehyde I20 4 2 0.2M Cacodylate Buffer (pl-I 7.4) 30 4 3 0.2M Cacodylate BuITer (pH 7.4) 30 4 4 0.2M Cacodylate Buffer (pH 7.4) 30 4 5 2% Osmic Acid [20 4 6 0.2M Cacodylate Buffer (pH 7.4) 30 4 7 50% Alcohol IO 4 8 50% Alcohol [0 4 9 Alcohol 15 4 I0 Alcohol 15 20 II Alcohol 30 20 I2 100% Alcohol 30 20 I3 100% Alcohol Propylene Oxide (l to I) IS 20 I4 Propylene Oxide 3O 20 I5 Propylene Oxide 30 20 I6 Propylene Oxide Epon 812 (2 to I) 60 20 I7 Propylene Oxide Epon 812 (I to 2) 60 20 1s Epon 312 60 37 I9 Epon 8l2 60 37 20 Epon 8 l 2 60 37 ROTARY TRANSFER DISC ACTUATING MECHANISM The intermittent rotary motion or indexing motion and the up and down movement of the rotary transfer disc 5 as described hereinbefore is effected by a rotary disc actuating mechanism generally designated by reference numeral 14 in FIG. 2.

The actuating mechanism 14 comprises an electric motor 15 stationarily mounted on a mounting base 16 rigidly secured to the inner wall of the housing 3. As also shown in FIG. 2B, the output shaft of the motor 15 is connected via a coupling 15a to a worm, not shown, which worm is in turn in mesh with a worm wheel 17. The worm wheel 17 has a shaft 17a on which is rigidly mounted a bevel gear 18. This bevel gear 18 is in mesh with another bevel gear 19 (FIG. 2) having a shaft 19a, which extends upward and connected via a coupling 20 to a rotary shaft 21. It will thus be seen that when the motor 15 is operated the shaft 21 is accordingly rotated.

On a base plate 22 rigidly mounted on the top of the housing 3, there is secured upright studs 23 one of which is shown in FIG. 2. These studs 23 have secured thereto a disc 24. The disc 24 and the base plate 22 cooperate to rotatably support the shaft 21.

As is clearly shown in FIG. 2A, the shaft 21 has a transverse arm 21a having a geneva pin 25, which engages inter-tooth spaces of a geneva wheel 26 successively. The geneva wheel 26 and pin 25 constitute a well known geneva mechanism for producing intermittent turning motion. The wheel 26 is mounted on the central shaft 6. It will thus be seen that when the motor 15 is operated, the shaft 6 and hence the transfer disc 5 undergo intermittent rotary motion or indexing motion.

As is shown in FIGS. 2 and 2B, the shaft 17a of the bevel gear 18 has rigidly mounted thereon a cam plate 27. On the other hand, a bracket 28 (FIG. 2) is secured under the base plate 22 and a lever 29 is pivotally mounted on the bracket at 28a. The lever 29 carries on an intermediate part thereof a cam follower 29a which rides on the peripheral surface of the cam plate 27. The free end of the lever 29 is pivotally connected at 30 to the lower end of the central shaft 6.

It will thus be seen that when the motor is operated, the lever 29 is swung up and down by the cam plate 27 to cause the shaft 6 to move reciprocatively up and down. The geneva wheel 26 is mounted on the shaft 6 in a manner to transmit rotation to the shaft 6 but to be vertically slidable relative to the shaft. The disc 24, studs 23, shaft 21, geneva wheel 26 and other associated members are enclosed in a cover 31.

REAGENT TEMPERATURE CONTROL SYSTEM The temperature control of the reagents is carried out by a heat transfer medium circulating system. As shown in FIG. 2, the circulating system comprises an annular hollow jacket member 40 through which a heat transfer medium, such as water, can flow. Part of the bottom of the jacket member 40 is communicatively connected to the delivery side of a pump 42 by a conduit 41 and an inlet pipe 43, and another part of the bottom of the jacket member 40 is communicatively connected to a reservoir 44 for storing the heat transfer medium through an outlet pipe 45 and a conduit 46. It will thus be apparent that the heat transfer medium in the reservoir 44 is circulated by the pump 42 through the conduit 41, the pipe 43, the interior of the jacket member 40, the pipe 45 and the conduit 46 back into the reservoir 44.

A refrigerating unit 49 is associated with the reservoir 44 and has a refrigerant circulating coil 50 disposed in the reservoir 44 for cooling the heat transfer medium. The reservoir 44 has also associated therewith a main heating coil 51 and an auxiliary heating coil 52. These coils 51 and 52 may be in the form of an electric heating coil. When the temperature of the heat transfer medium is to be maintained at 4C, for example, the refrigerating unit 49 is put in operation while the heating coils are not in operation. On the other hand, when the temperature of the heat transfer medium is to be maintained at C, for example, the operation of the refrig crating unit 49 is stopped, and only the main heating coil 51 is energized, while, when the temperature of the heat transfer medium is to be maintained at 37C, for example, the auxiliary heating coil 52 is additionary operated to increase the heating capacity.

As shown in FIGS. 2 and 5, the jacket member 40 is of a rectangular cross section and has in the upper surface thereof a series of pockets 54 disposed in an annular arrangement in circumferentially equally spacedapart relationship. Each of the pockets 54 is in the form of a cylindrical recess with a bottom 54a and is configured to removably receive the beaker or receptacle 12 therein as is most clearly shown in FIG. 5. Thus, it will be apparent that the liquid reagents in the receptacles 12 received in the pockets 54 are cooled or heated by the heat transfer medium through the heat transfer across the walls of the receptacles 12 and pockets 54.

In order to maintain a constant-temperature condition of the liquid reagents in the receptacles, a temperature control device may be provided to detect the temperature of the heat transfer medium flowing through the jacket member 40 so as to control the refrigerating unit 49 and the heating coils 51 and 52.

In FIG. 2, the inlet and outlet pipes 43 and 45 are shown as provided at diametrically opposite portions of the annular jacket member 40 for the purpose of clarity, but these pipes are actually provided at positions corresponding to the positions of the receptacles numbered 1 and 20", respectively, as shown in FIG. 4. In this case, a partition wall 56 is provided to cause the heat transfer medium introduced through the inlet pipe 43 into the jacket member 40 to flow along the annular path within the member 40 to the outlet-pipe 45.

REAGENT RECEPTACLE SEALING DEVICE As is most clearly shown in FIG. 5, on the upper surface of the jacket member 40 there is secured an annular pad 60 made of a material such as synthetic resin, which is disposed around the opening periphery of each receptacle-receiving pocket 54. The height or thickness of the pad 60 is such that the sum of the thickness of the pad and the depth of the pocket 54 is slightly smaller than the height of the receptacle 12, whereby the top edge of thereceptacle 12 projects upward beyond the upper surface of the pad 60 to facilitate insertion and removal of the receptacle into and out'of the pocket 54.

The rod 7 carrying the sealing cap 8 and the basket 9 has on the lower end thereof a fitting 7a having a vertical through hole 61 therein. The basket 9 has a stern 9a extending upward therefrom and this stem 9a is slidably inserted into the hole 61 and secured in position by a set screw 62 transversely threaded in the fitting 7a. It will be seen that the vertical position of the basket 9 can be adjusted by loosening the set screw 62.

The fitting has an enlarged part or flange 63 and male threads 64 below the flange. Under the lower surface of the flange 63, there is disposed a packing ring 65 and the cap 8 of an inverted cup-shaped form is placed on and around the ring 65. With the male threads 64 is engaged a nut 66 having female threads. When the nut 66 is tightened against the packing ring 65, the ring 65 is deformed to tightly hold the cap 8 on the fitting 7a. The lower periphery of the cap 8 is provided with an annular packing 67 which is adapted to tightly abut the upper surface of the pad 60 when the basket 9 is lowered to the position of FIG. 5 at which the basket 9 is completely dipped in the liquid reagent in the receptacle 12. It will be noted that, in the condition shown in FIG. 5, the interior space within the cap 8 and the pocket 54 is completely sealed from the outside. The cap 8 may have rigidly fixed thereto a bearing member 8a through which the stem 9a passes.

VACUUM SYSTEM As shown in FIG. 5, there is provided a suction pipe 70 passing horizontally through the pad 60 and communicating at one end thereof with the interior space of the pocket 54. The other end of the pipe 70 is communicatively connected to a riser pipe 71 secured to the base plate 22 and having a strainer or filler 72 therein. The filter 72 can be inserted into the interior of the riser pipe 71 through the top opening thereof, and after the insertion, a top cover 73 is threadedly secured on the top of the pipe 71. As shown in FIG. 2, the

lower end of the pipe 71 is connected to a conduit 74 leading to a vacuum pump 75 through a solenoid valve 76.

When processing the specimen in the first receptacle numbered 1, it is generally desirable to have the interior space of the receptacle evacuated because such an evacuation is effective to remove air bubbles and moisture existing in fresh tissue to be processed, and such removal greatly facilitates and improves ingress or impregnation of the reagent into the tissue. When the reagent is a viscous liquid such as epon as is used in the receptacles numbered 18, 19 and 20, the application of vacuum is also useful to improve impregnation of the viscous liquid into the tissue. From this point of view, the suction pipe 70 and the associated riser pipe 71 are provided for each of the pockets 54 receiving the receptacles numbered 1, 18, 19 and 20, as shown in FIG. 4. The solenoid valve ,76 is provided for each of the four suction pipes 70, while the suction pump 75 is used commonly for the four suction pipes 70. It will be apparent that, when the vacuum pump 75 is driven and one of the solenoid valve 76 is opened, the interior space of the cap 8 and, therefore, one of the receptacle 12 is evacuated and maintained at sub-atmospheric pressure to improve and accelerate the impregnation of the reagent.

EXHAUST SYSTEM Referring to FIG. 2, the upper cylindrical hood 4 has on the lower edge thereof an annular packing 4a which sealingly engages the bottom surface of an annular dish on the base plate 22. The top wall of the hood 4 is formed with an exhaust opening 80 to which an exhaust conduit 81 is connected. The conduit 81 extends downward along the side surface of the hood 4 into the interior of the lower housing 3. The lower end of the conduit 81 is connected by means of a connecting bend 82 to an exhaust pipe 83 having therein a filter element 84 and an exhaust blower 85. The pipe 83 has an exhaust outlet 86. It will be readily seen that, when the blower 85 is driven, irritating gases or vapours which are generated from the reagents into the interior space of the hood 4 will be exhausted through the conduit 81 and pipe 83 to the outside after having been filtered by the filter element 84.

DRY AIR SUPPLY SYSTEM As shown in F IG. 6, the lower housing 3 of the apparatus encloses a pair of identical dry air supply devices 90. Each device 90 comprises acylindrical enclosure 91 containing drying agent 92 such as'silica gel therein. The enclosure 91 has also therein a pair of air filters 93 at both ends thereof and has wound around the outer wall thereof an electric heating coil 94. One end of the enclosure 91 is connected to the delivery side of an air blower 95, and the other end thereof is connected through a strainer 96 to a three-way solenoid value 97. From the valve 97, a dry air supply conduit 98 extends upward into the interior space of the hood 4. An exhaust pipe 99 extends from the valve 97.

The dry air supply devices 90 are alternately operated for supplying dry air into the hood 4. When one of the devices 90 is to be operated, the solenoid valve 97 thereof is so operated as to cause the supply conduit 98 to communicate with the strainer 96 and the blower 96 is put in operation. Thus, air is forced through the filter 93, drying agent 92, filter 93, strainer 96 and valve 97, and dry air is supplied into the hood 4 through the supply conduit 98. When one device 90 is thus operating, the other device 90 undergoes a recovering cycle. That is, the solenoid valve 97 is changed over to communicate the strainer 96 with the exhaust pipe 99 and the heating coil 94 is energized. It will be seen that the drying agent 92 is heated by the coil 94, and moisture accumulated in the agent 92 druing the dry air supply cycle is dissipated from the agent by operating the blower 95 and is carried away through the exhaust pipe 99 to the outside. By such alternative use of the dry air supply devices, dry air is continuously fed into the hood 4, and the atmosphere within the hood is constantly maintained dry.

INDEXING DELAY DEVICE When a processing reagent is a viscous liquid such as epon, carryover of the reagent into the next reagent tends to occur as the basket is raised from the former reagent and indexed into the next reagent because the viscous liquid has a tendency to adhere to the basket and cannot completely drip into the reagent receptacle immediately after the basket has been raised. Since the processing reagents in the receptacles are of different kind from reagent to reagent, the carryover of a reagent into the next reagent is not desirable.

In order to avoid such a disadvantage, an indexing delay device is provided according to this invention. As shown in FIG. 2, the stationary disc 24 forming part of a framework for supporting the shafts 6 and 21 supports thereon a row of microswitches 100 only one of which is shown for clarity in FIG. 2. In the example shown, three such microswitches 100 are provided at successively adjoining positions as shown in FIG. 3.

Referring again to FIG. 2, the transfer disc 5 has rigidly secured thereto a downwardly extending pin 101 for actuating the microswitches 100 one after the other. It is to be noted that when the basket 9 is at a position directly above a receptacle containing a first epon, i.e., at a position directly above the receptacle numbered 18 (see FIG. 4), the actuating pin 101 is directly above the first microswitch 100.

As the transfer disc 5 is lowered to immerse the basket 9 into the first epon (No. l8), the pin 10] is also lowered to engage the actuating member of the first microswitch 100 to close the same.

Referring to the diagram of FIG. 7, when the switch 100 is closed, a relay R is energized, and its-normally open contact r10 is closed, while its normally closed contact r10 is opened. Then, a relay R is energized through a normally closed timer switch tm and the closed contact r10 to close a normally open contact r20, and the circuit passing through the contact r20, timer switch tm, and relay R makes a self-holding circult.

The main motor 15 is controlled by a main timer 103,

and when the transfer disc 5 is lowered to a position where the basket 5 is completely dipped in the first epon (No. 18), the main timer 103 operates to open the circuit to stop the main motor 15. After a preset time interval has elapsed, the main timer 103 again operates to activate the main motor 15, whereby the transfer disc 5 begins to rise and the switch 100 is opened.

When this occurs, the relay R is deenergized to close the contact rlC so that a relay R3 is energized. This relay & is a delay relay, and, after a predetermined time, for example, ten seconds, has elapsed, a normally open relay contact r3 is closed so that a relay R is energized. Then, a normally closed relay contact r4C is opened to stop the main motor 15. It will be noted that a predetermined time has elapsed before the main motor 15 is stopped after it was restarted. This time interval enables the motor 15 to rotate, after it has been restarted, until the cam plate 27 assumes an angular position at which the transfer disc is at its highest position.

The energization of the relay R also causes its normally open contact r40 to close, whereby an indexing delay timer 104 is set in operation. After its preset time, which allows the epon adhering to the raised basket to drip completely into the receptacle, has elapsed, the timer contact tm is opened, whereby the contact r20 is opened with the result that the relay R is deenergized to close the contact r4C, and the main motor is operated again to index the basket to the position of the second epon. At the positions of the second and third epons (Nos. 19 and the same operation as described above is repeated.

BASKET OSCILLATION SYSTEM For the purpose of promoting the processing, the basket 9 is oscillated or turned reciprocatively when it is being dipped in the reagents. The system for this purpose is driven by an auxiliary motor 110 secured to the mounting base 16 as shown in FIG. 2. The motor 110 has a vertical output shaft on the top of which is secured a drive coupling 111. As is also shown in FIG. 6, the central shaft 6 is a hollow shaft and a core shaft 6a is slidably passed through the shaft 6. The lower end of the core shaft6a has a driven coupling 112 on the lower end thereof. On the top of the core shaft 6a there is provided a crank mechanism 113 and a connecting rod 114 is pivoted at one end. The other end of the rod 114 is connected to a rocking mechanism 115 which is in turn connected to the upper end of the rod 7 associated with the basket 9.

It will be seen that when the transfer disc 5 is lowered, the driver coupling 112 engages the drive coupling 111, and the rotary motion is transmitted from the motor 110 to the core shaft 6a to oscillate the rod 7 and, therefore, the basket 9 which is now in the reagent. Thus, an agitating action is created to promote processing.

GENERAL CONTROL As is apparent from'the foregoing description, the indexing or intermittent motion and up-and-down move;

ment of the transfer disc 5 is carried out by the operation of the main motor 15, and this main motor is controlled automatically by the main timer 103. This main timer 103 is, for example, of the type comprising a punched tape and a tape reader useing a photoelectric sensing device.

As shown in FIG. 1, the apparatus 2 has on the front side thereof an enclosure 120 for enclosing such a timer device. The apparatus may also include a vacuum indicating pilot lamp 121, a temperature gauge 122 for the heat transfer medium, and a vacuum gauge 123. The apparatus may also include operation keys 124a and l24b for raising and lowering the hood 4 relative to the housing 3 for the charge and discharge of the tissue into and out of the apparatus as well as a knob 125 for change-over between automatic and manual control.

I claim:

1. In an apparatus for processing tissue for electron microscope examination, comprising means for arranging a series of processing reagent containing receptacles in a row with equal distances therebetween, transfer means for transferring a tissue-containing basket, said transfer means being located above said receptacles and mounted for indexing movement along the series of receptacles and for up and down movement to dip the basket and, therefore, the tissues therein into the processing reagents in the receptacles successively one by one, the improvement comprising sealing means associated with said transfer means and operative to seal temporarily from the outside the ambient atmosphere surrounding any one of the receptacles in which the basket is being dipped in the reagent, suction means associated with at least some of thereceptacles to evacuate air from the atmosphere surrounding said some receptacles thus sealed, series of processing reagent containing receptacles being arranged in an annular endless row, said transfer means being in the form of a rotary disc capable of being rotated around a center coaxial with the center of said annular endless row, said rotary disc having along the periphery thereof a series of mounting means of annular arrangement with equal distances therebetween corresponding to those between said receptacles, wherein one of said mounting means carries said basket and each of the remaining mounting means carries a lid which is adapted to cover and close an associated receptacle when the rotary disc is lowered to dip the basket in the reagent, thereby to prevent evaporation of the reagents contained in the receptacles other than that cooperating with the basket, a hood enclosing said rotary disc, receptacles, basket and lids and means for exhausting gases and vapors within said hood, and means for supplying dry air into theinterior space of said hood.

2. The apparatus as claimed in claim 1 wherein said sealing means comprises a sealing cap coaxially mounted above said basket and adapted to be lowered to sealingly confine therein a receptacle in which the basket is lowered for dipping in reagent.

3. The apparatus as claimed in claim 2 wherein eac of the receptacles has therearound an annular pad on which said sealing cap engages sealingly.

4. The apparatus as claimed in claim 2 wherein said sealing cap and said basket are in rigid connection with eachother.

5. The apparatus as claimed in claim 1 wherein said suction means has associated therewith means for actu-. ating the same in response toa predetermined down movement of said transfer means. 6. The apparatus as claimed in claim 1, further including means for delaying the indexing movement of the transfer means from one receptacle to the next receptacle, whereby excess reagent remaining in the basket raised from said one receptacle is allowed to drip when it has been dipped in the reagent. 

1. In an apparatus for processing tissue for electron microscope examination, comprising means for arranging a series of processing reagent containing receptacles in a row with equal distances therebetween, transfer means for transferring a tissuecontaining basket, said transfer means being located above said receptacles and mounted for indexing movement along the series of receptacles and for up and down movement to dip the basket and, therefore, the tissues therein into the processing reagents in the receptacles successively one by one, the improvement comprising sealing means associated with said transfer means and operative to seal temporarily from the outside the ambient atmosphere surrounding any one of the receptacles in which the basket is being dipped in the reagent, suction means associated with at least some of the receptacles to evacuate air from the atmosphere surrounding said some receptacles thus sealed, series of processing reagent containing receptacles being arranged in an annular endless row, said transfer means being in the form of a rotary disc capable of being rotated around a center coaxial with the center of said annular endless row, said rotary disc having along the periphery thereof a series of mounting means of annular arrangement with equal distances therebetween corresponding to those between said receptacles, wherein one of said mounting means carries said basket and each of the remaining mounting means carries a lid which is adapted to cover and close an associated receptacle when the rotary disc is lowered to dip the basket in the reagent, thereby to prevent evaporation of the reagents contained in the receptacles other than that cooperating with the basket, a hood enclosing said rotary disc, receptacles, basket and lids and means for exhausting gases and vapors within said hood, and means for supplying dry air into the interior space of said hood.
 2. The apparatus as claimed in claim 1 wherein said sealing means comprises a sealing cap coaxially mounted above said basket and adapted to be lowered to sealingly confine therein a receptacle in which the basket is lowered for dipping in reagent.
 3. The apparatus as claimed in claim 2 wherein each of the receptacles has therearound an annular pad on which said sealing cap engages sealingly.
 4. The apparatus as claimed in claim 2 wherein said sealing cap and said basket are in rigid connection with each other.
 5. The apparatus as claimed in claim 1 wherein said suction means has associated therewith means for actuating the same in response to a predetermined down movement of said transfer means.
 6. The apparatus as claimed in claim 1, further including means for delaying the indexing movement of the transfer means from one receptacle to the next receptacle, whereby excess reagent remaining in the basket raised from said one receptacle is allowed to drip into the latter.
 7. The apparatus as claimed in claim 1 wherein each of the lids is suspended from the associated mounting means through a flexible suspension means.
 8. The apparatus as claimed in claim 1, further including means for maintaining the reagents in the series of receptacles at respectively predetermined temperatures.
 9. The apparatus as claimed in claim 8 wherein said maintaining means comprises means for circulating a heat transfer medium in heat transfer relationship to be receptacles.
 10. The apparatus as claimed in claim 1, further including means for reciprocatively moving the basket when it has been dipped in the reagent. 